When Katherine Miller was 24, she saw a doctor for an array of symptoms including anemia, fainting, stomach pain and rectal bleeding. She received a diagnosis of irritable bowel syndrome. At the age of 25, after the full physical exam required for medical school admission, Miller was declared to be in peak fitness. At the age of 26, she died. Just before her death, when a follow-up colonoscopy and CT scan were finally done, colon cancer was found to have spread to her liver. While colon cancer discovered early is highly treatable, once it has metastasized, it is nearly always deadly.

I've found in nearly 100 interviews with cancer survivors under 40, such stories of symptoms being dismissed with the claim that "you are too young for cancer" are shockingly common.

In that sense, the image of Lance Armstrong as the poster boy of the young cancer survivor is misleading. It suggests that cancer is survivable when one is young. No matter how attractive this image, youth is not protective.

Some 70,000 Americans between the ages of 20 and 40 are being diagnosed with cancer every year. Even this number does not include those diagnosed in their 40s, who could have been diagnosed and treated in their 30s with higher chances of success. In fact, three-quarters of adults under age 40 who are diagnosed with cancer are diagnosed with late-stage cancers, giving them drastically reduced survival chances.

Younger people suffer from an intense "cancer burden." Often they have few savings to draw on during long treatments, have young children to support, face job discrimination and - if they survive - have a chronic condition that may cost thousands of dollars a year to treat, even with insurance.

Furthermore, the stereotypes about cancer lead to the intense alienation of young adults, who are often the youngest people in the chemotherapy room and who need to cope with the inexperience and misinformation from their friends, family, communities and physicians.

The recent focus of cancer research on early detection, genetic testing and over-treatment neglects the reasons for the under-detection of cancer in young adults. Attention to the prevalence of misdiagonosis is critical, given the inefficacy of current treatments for most later-stage cancers.

We desperately need to change how we think about the everyday doctor-patient interactions that lead to the successes and failures of cancer detection.

Everyone wants to believe they are immune, including the doctors who may shy away from believing a younger person sitting in their examination room may have cancer. However, the myth that cancer is a disease of older people leads to the late diagnoses, suffering and deaths of thousands of people each year.